Production method of multiple panes

ABSTRACT

The objective is to propose a production method of multiple panes which can be simple and nevertheless produce a multiple pane in its finished state which does not include any undesired protrusion from an external surface of a glass panel. The production method includes: hermetically bonding, with a sealing member, peripheries of paired glass panels disposed facing each other at a predetermined distance to form a space to be hermetically enclosed between the glass panels; evacuating air from the space through an outlet to make the space be in a reduced pressure state; and dividing, after the space is made be in the reduced pressure state, the space by a region forming member into an outlet region including the outlet and a reduced pressure region other than the outlet region.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is continuation of International Application No.PCT/JP2013/003128 which claims the benefit of priority of JapanesePatent Application No. 2012-114979, filed on May 18, 2012, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to methods of producing multiple panes inwhich paired glass panels are stacked with a reduced pressure spacein-between, and particularly relates to a production method of amultiple pane which an undesired protrusion such as an evacuation pipeused for pressure reduction does not remain after finishing

BACKGROUND ART

There has been commercialized a multiple pane. In the multiple pane, apair of glass panels are arranged facing each other, and a plurality ofspacers are interposed between the pair of glass panels, and the pair ofglass panels are bonded with a hermetically bonding member atperipheries thereof, and thus an inside space is defined by the pair ofglass panels and the hermetically bonding. The air in the inside spaceis exhausted to reduce the pressure of the inside space.

It is expected that the multiple pane in which the pressure of theinside space is reduced shows great thermally insulating effects, dewprevention effects, and sound insulating effects, as a result ofpresence of a vacuum layer whose pressure is lower than the atmosphericpressure between the pair of glass panels, relative to a multiple paneconstituted by two glass plate simply bonded to each other. Therefore,such multiple pane attracts great attentions as one of eco-glass incurrent situations in which the importance of energy strategy rises.

The multiple pane including the inside space with the reduced pressureis produced as follows: the peripheries of the pair of glass panels arehermetically bonded by applying the hermetically bonding seal oflow-melting glass frit therebetween and heating them to hermeticallybond the peripheries to form a space while a plurality of spacers ofmetal or ceramics are interposed to keep the predetermined distancebetween the glass panels, and thereafter air is evacuated from the spacevia an evacuation pipe of glass or metal. The multiple pane is producedthrough this production process, and thus the finished product of themultiple pane including the inside space with the reduced pressureincludes the evacuation pipe whose tip is closed. Hence, in the multiplepane constituted by transparent glass panels, the evacuation pipe maycause problems that appearance becomes poor and the inside space cannotbe kept in the reduced pressure state when the evacuation pipe isbroken. In view of this, with regard to the multiple pane used as awindow pane, for example, the multiple pane is used so that theevacuation pipe is positioned at the upper-right corner of the indoorside. In other words, the use of the multiple pane is limited so as toprevent visually and physically interference of the evacuation pipe.

In a technique which has been proposed as the conventional productionmethod of multiple pane with the reduced pressure, an evacuation pipe isembedded into one of glass panels until a center in a thicknessdirection, and the evacuation pipe is sealed with shield for preventinga junction of the glass panel and the evacuation pipe from sufferingfrom heat generated in sealing the evacuation pipe. According to thistechnique, the evacuation pipe remaining in the finished product isshortened (see patent literature 1 [JP 10-2161 A]). In anothertechnique, an evacuation pipe and a vicinity of a part, on which theevacuation pipe is situated, of a rear surface of a glass panel arecovered with a cover member of resin so as to form a gap between thecover member and a sealed tip of the evacuation pipe. According to thistechnique, breakage of the evacuation pipe caused by impacts fromoutside can be prevented (see patent literature 2 [JP 11-311069 A]).

According to the conventional production method of multiple panedescribed above, in the finished product, the evacuation pipe becomesshort, and thus the multiple pane can be easy in handling. Externalforce directly acting on the evacuation pipe can be suppressed, and thusit is possible to prevent an unwanted situation where the reducedpressure state cannot be maintained due to breakage of the evacuationpipe. Therefore, the conventional production method can giveadvantageous effects to an extent.

However, for example, in the techniques disclosed in patent literature1, it is necessary to form a recess in the glass panel and fix theevacuation pipe inside the recess in order to reduce an amount of partof the evacuation pipe protruding from the surface of the glass panel.Further, the shield disposed so that the temperature of the junction ofthe evacuation pipe and the glass plate becomes high at the time ofsealing the evacuation pipe is necessary. Thus, the production processof multiple pane becomes more complex. Additionally, according to thetechnique disclosed in patent literature 2, it is necessary to add thecover member, and this causes an increase in the number of parts.Further, it is necessary to add a step of attaching the cover member tothe rear surface, and this causes an increase in the number of steps.When the production process becomes more complex and the numbers ofparts and steps increase, the production cost of the multiple pane tendsto increase. Further, in the multiple panes formed by use of the aboveconventional techniques, the evacuation pipe still remains in thefinished product. Hence, such a protrusion from the rear surface of themultiple pane is present and therefore there is a problem of appearance,it is very difficult to perfectly eliminate a risk in which the spaceformed by the pair of glass panels cannot be kept in the reducedpressure state when the evacuation pipe is broken.

SUMMARY

In view of the above circumstances, the present invention has aimed topropose a production method of multiple panes which can be simple andnevertheless produce a multiple pane in its finished state which doesnot include any undesired protrusion from an external surface of a glasspanel.

The production method of multiple panes of the present disclosureincludes: hermetically bonding, with a hermetically-bonding member,peripheries of paired glass panels disposed facing each other at apredetermined distance to form a space to be hermetically enclosedbetween the glass panels; evacuating air from the space through anoutlet to make the space be in a reduced-pressure state; and dividing,after the space is made be in the reduced-pressure state, the space by aregion forming member into an outlet region including the outlet and areduced-pressure region other than the outlet region.

In the production method of multiple panes of the present disclosure,the space formed between the pair of glass panels hermetically bondedwith the hermetically-bonding member is made be in the reduced pressurestate, and subsequently the space is divided by the region formingmember into the outlet region and the reduced-pressure region. Hence,even when an evacuation pipe used for evacuation is removed for example,the reduced-pressure region is kept in the reduced-pressure state.Therefore, it is possible to easily produce a finished product of amultiple pane which does not include any undesired protrusion protrudedfrom an external surface of a glass panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan illustrating a configuration example of a multiple panewith an inside space having a reduced pressure which is produced by theproduction method of multiple panes of the present disclosure.

FIG. 2 is a section illustrating the configuration example of themultiple pane with the inside space having the reduced pressure which isproduced by the production method of multiple panes of the presentdisclosure.

FIG. 3 is a plan which relates to the production method of multiplepanes of the first embodiment and illustrates a state in which ahermetically-bonding member and a region forming member have not beenmelted yet.

FIG. 4 is a section which relates to the production method of multiplepanes of the first embodiment and illustrates the state in which thehermetically-bonding member and the region forming member have not beenmelted yet.

FIG. 5 is a diagram illustrating examples of configuration conditions ofa fusing process and an evacuating process in the production method ofmultiple panes of the first embodiment.

FIG. 6 is a section which relates to the production method of multiplepanes of the first embodiment and illustrates a state in which a spacebetween paired glass panels is divided by the region forming member.

FIG. 7 is a diagram illustrating other examples of the configurationconditions of the fusing process and the evacuating process in theproduction method of multiple panes of the first embodiment.

FIG. 8 is an enlarged plan illustrating a primary part of the firstmodification of the region forming member in the production method ofmultiple panes of the first embodiment.

FIG. 9 is an enlarged plan illustrating a primary part of the secondmodification of the region forming member in the production method ofmultiple panes of the first embodiment.

FIG. 10 is an enlarged plan illustrating a primary part of a finishedproduct including the modification of the region forming member in theproduction method of multiple panes of the first embodiment.

FIG. 11 is a plan which relates to the production method of multiplepanes of the second embodiment and illustrates a state in which ahermetically-bonding member and a region forming member have not beenmelted yet.

FIG. 12 is a section which relates to the production method of multiplepanes of the second embodiment and illustrates the state in which thehermetically-bonding member and the region forming member have not beenmelted yet.

FIG. 13 is a diagram illustrating a difference in appearance between anapplied part and a melted and spread part of the region forming member.

FIG. 14 is a section which relates to a case where a height keepingmember is disposed at a portion on which the hermetically-bonding memberis to be formed with regard to the production method of multiple panesof the present disclosure and illustrates a state in which the innerspace is divided by fusing the region forming member.

The figures depict one or more implementation in accordance with thepresent teaching, by way of example only, not by way of limitations.

DETAILED DESCRIPTION

The production method of multiple panes of the present disclosureincludes: hermetically bonding, with a hermetically-bonding member,peripheries of paired glass panels disposed facing each other at apredetermined distance to form a space to be hermetically enclosedbetween the glass panels; evacuating air from the space through anoutlet to make the space be in a reduced-pressure state; and dividing,after the space is made be in the reduced-pressure state, the space by aregion forming member into an outlet region including the outlet and areduced-pressure region other than the outlet region.

In the production method of multiple panes, after the space between thepair of glass panels whose peripheries are hermetically bonded with thehermetically-bonding member is made be in the reduced-pressure state,the space is divided into the outlet region and the reduced-pressureregion by the region forming member. According to the production methodof this present disclosure, the space between the pair of glass panelsmade be in the reduced-pressure state is divided into the outlet regionand the reduced-pressure region by the region forming member. Therefore,even when an evacuation pipe used for evacuation is removed thereafter,it is possible to keep the reduced-pressure region in thereduced-pressure state. Consequently, it is possible to produce amultiple pane which can keep desired properties such as thermallyinsulating properties, dew condensation prevention properties, and soundinsulating properties and nevertheless does not include any undesiredprotrusion from an external surface of a glass panel.

Note that, in the present description, the phrase that the pressure ofthe space between the pair of glass panels is reduced means that thespace between the pair of glass panels is made be in a state in whichthe pressure is lower than an outside atmospheric pressure. Further, thereduced-pressure state in the present description means a state in whichthe pressure of an inside of the space is lower than the outsideatmospheric pressure, and thus may include a so-called vacuum stateobtained by reducing the pressure by evacuating air from the space,irrespective of the degree of vacuum. Further, a state resulting fromevacuating air inside the space and then filling the space with at leastone of various gases such as an inert gas is included in thereduced-pressure state of the present description, when the pressure ofthe gas inside the space is finally lower than the atmospheric pressure.

Further, in a preferable aspect of the production method of multiplepanes of the above present disclosure, the region forming memberincludes an air passage interconnecting the outlet region and thereduced-pressure region under a condition where the space is formed; andafter the space is made be in the reduced-pressure state, the space isdivided into the outlet region and the reduced-pressure region byclosing the air passage. According to this aspect, it is possible toeasily divide the space into the outlet region and the reduced-pressureregion after the space between the pair of glass panels is made be inthe reduced-pressure state.

In this case, the air passage is an interval of the region formingmember formed in a discontinuous shape, and after the space is made bein the reduced-pressure state, the interval can be closed by melting theregion forming member.

Further, in another preferable aspect of the production method ofmultiple panes of the above present disclosure, a formation height ofthe region forming member before being melted is less than a formationheight of the hermetically-bonding member before being melted; and afterthe space is made be in the reduced-pressure state under a conditionwhere the pair of glass panels are hermetically bonded by melting thehermetically-bonding member, the space is divided into the outlet regionand the reduced-pressure region by the region forming member bydecreasing the distance between the pair of glass panels. According tothis aspect, it is possible to easily divide the space in thereduced-pressure state into the outlet region and the reduced-pressureregion by adjusting the distance between the pair of glass panels.

Further, in another preferable aspect, a melting temperature of theregion forming member is higher than a melting temperature of thehermetically-bonding member; the space is formed by hermetically bondingthe pair of glass panels at a temperature causing melting of thehermetically-bonding member to form the space; and after the space ismade be in the reduced-pressure state, the space is divided into theoutlet region and the reduced-pressure region by melting the regionforming member at a temperature causing melting of the region formingmember. According to this aspect, it is possible to easily divide thespace in the reduced-pressure state into the outlet region and thereduced-pressure region by adjusting the melting temperatures of theregion forming member and the hermetically-bonding member.

Further, in another preferable aspect, after the space is formed byconducting melting inside a furnace to melt the hermetically-bondingmember, and subsequently the space is made be in the reduced-pressurestate outside the furnace, the space is divided into the outlet regionand the reduced-pressure region by conducting again melting inside thefurnace to melt the region forming member. According to this aspect, thestep of evacuating the space formed between the glass panels can beconducted at a lower temperature than the steps of melting thehermetically-bonding member and the region forming member. Therefore,the space can be evacuated to be in the reduced-pressure state by use ofinexpensive and simple equipment.

Further, in another preferable aspect, the outlet is formed in at leastone of the pair of glass panels. In another aspect, the space is made bein the reduced-pressure state by use of an evacuation pipe connected tothe outlet; and the evacuation pipe is removed after the space isdivided into the outlet region and the reduced-pressure region.According to each aspect, the multiple pane can be produced by use ofmanufacture equipment capable of reducing the pressure of the spacethrough the evacuation pipe connected to the outlet.

Further, in another preferable aspect, the hermetically-bonding memberand the region forming member are made from glass frit. The glass fritis generally used as seal for forming a hermetically enclosed space bymelting the seal by heat, and consequently, the multiple pane can beproduced at a lowered cost.

Further, in another preferable aspect, a spacer for keeping a gapbetween the pair of glass panels is disposed on a surface of at leastone of the pair of glass panels. According to this aspect, it ispossible to accurately keep the gap between the pair of glass panels andto produce a multiple pane with high resistance to external impacts.

Further, in another preferable aspect, a height keeping member forkeeping a gap between the pair of glass panels is disposed at a portionon which the hermetically-bonding member is to be formed. According tothis aspect, even at the peripheries at which the hermetically-bondingmember is formed, the length of the gap between the pair of glass panelscan be kept to a predetermined length.

Further, in another preferable aspect, at least one of the spacer andthe height keeping member is formed by photolithography. By using thephotolithography, the spacer or the height keeping member having apredetermined shape can be disposed accurately at a predeterminedposition.

Hereinafter, the method of producing multiple panes of the presentdisclosure is described with reference to the drawings.

Note that, for convenience of explanation, the drawings referred belowrelate to the production method of multiple panes of the presentdisclosure and the multiple pane produced by the method of the presentdisclosure, and illustrate in a simplified manner mainly portionsnecessary for describing the disclosure. Therefore, the multiple panesdescribed with reference to the drawings may have any configurationwhich is not shown in the drawings referred. Furthermore, dimensions ofmembers shown in the drawings do not necessarily reflect dimensions anddimensional ratios of members in practice, exactly.

First Embodiment

First, the configuration of the multiple pane produced by the productionmethod of multiple panes of the present embodiment is described withreference to FIG. 1 and FIG. 2.

FIG. 1 is a plan illustrating a schematic configuration of a finishedproduct of the multiple pane produced by the production method of themultiple pane of the present disclosure. Further, FIG. 2 is a sectionillustrating a schematic configuration of a finished product of themultiple pane produced by the production method of the multiple pane ofthe present disclosure. Note that, FIG. 2 is a view illustrating asectional structure taken along line X-X′ in FIG. 1.

As shown in FIG. 1 and FIG. 2, the multiple pane 1 produced by theproduction method of the present disclosure includes: a rear glass panel2 and a front glass panel 3 defined as paired glass panels disposedfacing each other; and a frit seal 4 defined as a hermetically-bondingmember hermetically bonding peripheries of the glass panels 2 and 3 sothat a space A to be hermetically enclosed is formed between the glasspanel 2 and the glass panel 3.

Note that, to keep a distance between the glass panel 2 and the glasspanel 3 to a predetermined distance, spacers 6 are disposed on an insideof a region, on which the frit seal 4 is applied, of the rear glasspanel 2.

In the production method of the multiple pane of the present embodiment,air inside the space A is evacuated through an outlet 7 of the rearglass panel 2 to make the space A be in a reduced-pressure state, andthereafter the space A is divided by, a partition 5 serving as a regionforming member, into an outlet region B including the outlet 7 and areduced-pressure region C defined as a region other than the outletregion. Therefore, in the multiple pane 1 in a finished-state shown inFIG. 1 and FIG. 2, the reduced-pressure state of the reduced-pressureregion C can be maintained. Further, after the space A is divided intothe outlet region B and the reduced-pressure region C by the partition5, an evacuation pipe connected to the outlet 7 is removed. Hence, theoutlet region B is spatially connected to the outside and thus theoutlet region B is filled with air.

As described above, in the multiple pane 1 produced by the productionmethod of the present embodiment, the reduced-pressure region C whichoccupies most of the space A formed between the pair of glass panels 2and 3 is kept in the reduced-pressure state, and thereby properties(e.g., a thermally insulating effect, a dew condensation preventioneffect, and a sound insulating effect) inherent to a multiple pane inwhich the pressure of the inside space is reduced can be obtained.Additionally, the evacuation pipe used for evacuating the space A hasbeen removed, and therefore, as shown in FIG. 2, there is no protrusionprotruded outside from the rear side of the glass panel 2 of themultiple pane 1, and consequently a disadvantage caused by the presenceof the protruded evacuation pipe at the time of using and transferringthe multiple pane 1 can be solved. Further, the evacuation pipe has beenremoved, and thus it is possible to avoid an undesired situation wherethe whole space between the glass panels 2 and 3 of the multiple pane 1is not in the reduced-pressure state due to breakage of the evacuationpipe.

Hereinafter, the first example of the production method for the finishedproduct of the multiple pane 1 described with reference to FIG. 1 andFIG. 2 is described as the production method of multiple panes of thepresent embodiment.

FIG. 3 and FIG. 4 are diagrams for describing the first example of theproduction method for the finished product of the multiple pane 1described with reference to FIG. 1 and FIG. 2. FIG. 3 is a planillustrating a state in which the rear glass panel 2 and the front glasspanel 3 have not been hermetically bonded with the frit seal 4 yet. FIG.4 is a section illustrating a state in which the rear glass panel 2 andthe front glass panel 3 have not been hermetically bonded with the fritseal 4 yet. FIG. 4 is a view illustrating a sectional structure takenalong line Y-Y′ in FIG. 3.

As shown in FIG. 3 and FIG. 4, in the production method of multiplepanes of the present embodiment, the frit seal 4 in a frame shapeserving as the hermetically-bonding member is applied on a peripheralportion of a front surface 2 a of the rear glass panel 2, which is asurface facing the front glass panel 3. Further, the outlet 7penetrating through the glass panel 2 is formed in a vicinity of acorner of the rear glass panel 2. Additionally, an evacuation pipe 8 isprovided to a rear surface 2 b of the glass panel 2 to be connected tothe outlet 7. Note that, in the multiple pane described in the presentembodiment, the evacuation pipe 8 is made of glass, and an innerdiameter of the evacuation pipe 8 is equal to a diameter of the outlet7. The evacuation pipe 8 is connected to the outlet 7 by a conventionalmethod such as glass welding and a method using molten metal used aswelding material. Note that, the evacuation pipe 8 may be theaforementioned glass pipe or a metal pipe.

The glass panel used in the multiple pane used for explanation of theproduction method of the present embodiment may be selected from variousglass panels made of soda-lime glass, high-strain glass, chemicallytoughened glass, non-alkali glass, quartz glass, Neoceram, physicallytoughened glass, and the like. Note that, in the present embodiment,examples of the glass panel 2 and the glass panel 3 have the same shapeand the thickness. However, such glass panels may have different sizesand thicknesses. Further, the glass panel can be selected in accordancewith its application from glass panels with various sizes including aglass panel which is several cm on a side and a glass panel which is ina range of about 2 to 3 m on a side at maximum. Additionally, the glasspanel can be selected in accordance with its application from glasspanels with various sizes including a glass panel with a thickness in arange of about 2 to 3 mm and a glass panel with a thickness of about 20mm.

The partition 5 serving as the region forming member is formed on thefront surface 2 a of the glass panel 2 so that ends of the partition 5are connected to the frit seal 4 so as to surround the outlet 7 togetherwith the frit seal 4. In the present embodiment, the same low-meltingfrit glass is used for the frit seal 4 hermetically bonding the pair ofglass panels 2 and 3 and the partition 5.

In more detail, by way of one example, it is possible to use abismuth-based seal frit paste including: 60 to 75% of a glass componentwhich is composed mostly of bismuth oxide and includes 70% or more ofBi₂O₃, 5 to 15% of each of B₂O₃ and ZnO, and 10% or less of othercomponents; 20 to 30% of zinc-silica oxide; and 5 to 15% of a mixture oforganic substances such as ethylcellulose, terpineol, and polyisoutylmethacrylate. This frit glass has a softening point of 434° C.

Note that, the frit glass used for the frit seal 4 and the partition 5may be selected from lead-based frit and vanadium-based frit in additionto the bismuth-based frit. Further, seal made of low-melting metal orresin may be used for the hermetically-bonding member and the regionforming member as an alternative to the frit glass.

In a state where the frit seal 4 and the partition 5 have not beenmelted yet, a slit 5 a serving as an air passage is formed to penetratethrough the partition 5, and the partition 5 is discontinuous at a partwhere this slit is formed. In other words, the slit 5 a formed in thepartition 5 spatially interconnects opposite parts of the space A formedby the pair of glass panels 2 and 3 and the frit seal 4 with regard tothe partition 5.

A plurality of spacers 6 are arranged in lengthwise and width directionsat regular intervals on the front surface 2 a of the glass panel 2 so asto be positioned in an opposite side of the partition 5 from a sidewhere the outlet 7 is formed. For example, each of the spacers 6included in the multiple pane of the present embodiment has acylindrical shape with a diameter of 1 mm and a height of 100 μm, andeach of arrangement intervals in lengthwise and width directions is 2cm. The shape of the spacer is not limited to the above cylindricalshape and may be selected from various types of shapes such as a prismshape and a spherical shape. Further, the size of the spacer, the numberof arranged spacers, the interval of spacers, and the arrangementpattern of spacers are not limited to the aforementioned instances, andmay be appropriately selected in accordance with the size and thicknessof the glass panel to be used.

Further, in the production method of the present embodiment, the spacer6 is made of photo-curable resin by photolithography before the fritseal 4 is applied on the front surface 2 a of the glass panel 2, and inthis photolithography, photo-curable resin is applied on the entirefront surface 2 a to form a film with a predetermined thickness, andthereafter the film is exposed to light with a mask so as to cure intendparts of the film to form the spacers 6, and then undesired part of thefilm is removed by washing. By using the photolithography in thismanner, the spacers with the predetermined size and section can bedisposed at the predetermined positions accurately. Note that, when thespacers 6 are made of transparent photo-curable resin, the spacers 6 canbe less likely to be visually perceived when the multiple pane 1 isused.

The material of the spacer 6 is not limited to the aforementionedphoto-curable resin, and may be selected from various materials whichare not melted in a heating process described later. Further, instead ofusing the photolithography, spacers made of material such as metal canbe dispersedly fixed or bonded at predetermined positions in the frontsurface 2 a of the glass panel 2 on the rear side in a similar manner toa conventional multiple pane. Note that, when the formation andarrangement of the spacers are conducted without using thephotolithography, it is preferable that the spacers be in a spherical orcuboidal shape. In this case, even when the spacers disposed on thesurface of the glass panel are unintendedly directed in differentdirections, it is possible to accurately set the distance between thepair of glass panels.

Note that, the multiple pane produced by the production method of thepresent disclosure need not necessarily include the spacer, and may bedevoid of the spacer. Further, the spacer may be formed on a surface ofthe glass panel on the front side facing inside.

As shown in FIG. 4, when the frit seal 4 and the partition 5 have notbeen melted yet, the frit seal 4 and the partition 5 are formed to betaller than the spacer 6. For this reason, the glass panel 3 on thefront side is disposed on the tops of the frit seal 4 and the partition5, and gaps are formed between the glass panel 3 and the tops of thespacers 6.

FIG. 5 is a diagram illustrating examples of configuration conditions ofa melting process of melting the frit seal 4 and the partition 5 and anevacuating process of evacuating air from the space between the pair ofglass panels 2 and 3 in the production method of multiple panes of thepresent embodiment.

As shown in FIG. 5 in the first melting process, first a desiredtemperature of a furnace is set to a temperature (e.g., 450° C.) higherthan a softening point temperature of 434° C. of the glass frit used forthe frit seal 4 and the partition 5. In this process, the frit seal 4starts to melt, and thus the peripheries of the pair of glass panels 2and 3 are hermetically bonded, and thereby the space A to behermetically enclosed is formed between the pair of glass panels 2 and3. Simultaneously, the partition 5 also starts to melt, and thus thepartition 5 is welded to the glass panel 2 and the glass panel 3.However, the furnace temperature in the first melting process is set toa temperature of 450° C. which is slightly higher than the softeningpoint temperature of the glass frit, and therefore the partition 5 isnot greatly changed in shape, and thus the slit 5 a has not been closedyet. In the first melting process, it is important that the slit 5 aformed in the partition 5 has not been closed yet. Hence, the furnacetemperature is kept at the maximum temperature of 450° C. in the firstmelting process, and a continuous period (required period) of melting isset to an extent that the slit 5 a of the partition 5 is not closed. Inthe present embodiment, the continuous period (T1) in this first meltingprocess is 10 minutes, for example.

Subsequently, as shown in FIG. 5, the evacuating process begins. In theevacuating process, the temperature inside the furnace is temporarilydecreased down to a temperature (e.g., 380° C.) equal to or less thanthe melting-point temperature of 434° C. of the glass frit andsimultaneously air is evacuated from the space A with a vacuum pump.During the evacuating process, the temperature inside the furnace is setto be lower than the softening point temperature, and thus the frit seal4 and the partition 5 are not melted and changed in shape.

In view of ensuring the thermally insulating properties necessary forthe multiple pane, it is preferable that the degree of vacuum of thespace A be equal to or less than 0.1 Pa. The thermally insulatingproperties of the multiple pane increase with an increase in the degreeof vacuum. However, to obtain the higher degree of vacuum, it isnecessary to improve the performance of the vacuum pump and increase theevacuation period, and this may cause an increase in the productioncost. Hence, in view of the production cost, it is preferable that thedegree of vacuum be kept to a level sufficient to ensure the propertiesnecessary for the multiple pane and be not increased more thannecessary.

Note that, when the desired temperature in the evacuating process islowered intentionally, it takes time to increase the temperature to atemperature for the second melting process described later. Hence, inview of shortening a necessary period for the whole of the meltingprocess and the evacuating process, it is effective to set the desiredtemperature at the time of starting the evacuating process to atemperature slightly lower than the softening point temperature of theglass frit. For example, when the desired temperature of the evacuatingprocess is 420° C. and the continuous period (T2) is 120 minutes, thespace inside the multiple pane can be evacuated effectively.

Next, as shown in FIG. 5, while the space A is evacuated, thetemperature of the furnace is increased up to 465° C. for the secondmelting process. When the evacuation of the space A continues, theatmospheric pressure may cause external force narrowing the gap betweenthe pair of glass panels 2 and 3 and consequently, the glass panel 2 andthe glass panel 3 are pressed so that the distance therebetween isdecreased. In the multiple pane produced by the present embodiment, byway of example, the spacers 6 with the height of 100 μm are disposed,and thus the distance between the pair of glass panels 2 and 3 is keptequal to the height of 100 μm of the spacers. The force causing adecrease in the distance between the glass panels 2 and 3 occurs, andtherefore the frit seal 4 and the partition 5 which are melted arepressed from above and below. Therefore, in a plan view, the widths ofthe frit seal 4 and the partition 5 are increased. Hence, the pair ofglass panels 2 and 3 are hermetically bonded firmly and successfullywith the frit seal 4, and the slit 5 a formed in the partition 5 as theair passage is narrowed and thus closed. When the slit 5 a of thepartition 5 is closed, the space A is divided into the outlet region Bwhich is a space including the outlet 7 and the reduced-pressure regionC which is a space other than the outlet region. Note that, in thesecond melting process, mechanical pressing force may be applied to atleast one of the glass panels to decrease the distance between the glasspanels, if necessary.

In the second melting process, it is important that as described above,the partition 5 is sufficiently melted and thus the slit 5 a serving asthe air passage is successfully closed. By way of one example, when thecontinuous period (T3) at the desired temperature of 465° C. in thesecond melting process is 30 minutes, it is possible to successfullydivide by the partition 5 the space A into the outlet region B and thereduced-pressure region C.

As shown in the section of FIG. 6, the distance between the glass panel2 and the glass panel 3 is set to the predetermined distance determinedby the spacer 6, and the slit 5 a of the partition 5 is wholly closedand thus the space A is perfectly divided into the outlet region B andthe reduced-pressure region C. Subsequently, temperature of the furnaceis decreased and then the multiple pane is taken out from the furnace.

As described above, the space A is made be in the reduced-pressure stateby evacuating air from the space A through the outlet 7 of the glasspanel 2, and subsequently the space A is divided by the partition 5 intothe outlet region B and the reduced-pressure region C. In the stateshown in FIG. 6, the reduced-pressure region C is kept in thereduced-pressure state. In this state shown in FIG. 6, the evacuationpipe 8 is removed and thereby the finished product of the multiple pane1 described with reference to FIG. 1 and FIG. 2 can be obtained. Notethat, after the evacuation pipe 8 is disconnected from the vacuum pump,the inside of the outlet region B has the atmospheric pressure as withthe outside. Hence, it is easy to remove the evacuation pipe 8.

FIG. 7 shows other configuration conditions of the melting process ofmelting the frit seal 4 and the partition 5 and the evacuating processof evacuating air from the space A between the pair of glass panels 2and 3 in the production method of multiple panes of the presentembodiment. The configuration conditions shown in FIG. 7 are differentfrom the configuration conditions shown in FIG. 5 in that thetemperature of the multiple pane is decreased down to the roomtemperature after the first melting process.

First, the first melting process of melting the frit seal 4 tohermetically bond the pair of glass panels 2 and 3 so as to form thespace A is performed. The configuration condition of the first meltingprocess can be same as that shown in FIG. 5, and thus the maximumachieving temperature is 450° C. higher than the softening pointtemperature 434° C. of the glass frit used for the frit seal 4 and thepartition 5 and the continuous period (T4) is 10 minutes, by way of oneexample. Subsequently, the temperature of the multiple pane is decreaseddown to the room temperature by taking out the multiple pane from thefurnace or the like.

Thereafter, at the room temperature, the evacuating process ofevacuating air from the space A through the evacuation pipe 8 with thevacuum pump to obtain the space A with the predetermined degree ofvacuum is conducted. The desired period (T5) in the evacuating processis 300 minutes, for example.

In the other configuration condition example shown in FIG. 7, at the endof the evacuation process, under a condition where the degree of vacuumof the space A is a predetermined value such as 0.1 Pa or less, sealingthe tip of the evacuation pipe 8 to enclose the space A, so calledtip-off is conducted. By doing so, even when the multiple pane in whichthe space A formed by the pair of glass panels has the predetermineddegree of vacuum is detached from the vacuum pump, the space A can bekept in the reduced-pressure state.

After the evacuating process, the multiple pane in which the evacuationpipe 8 has been subjected to the tip-off is placed inside the furnaceagain, and the second melting process of the maximum temperature of 465°C. and the continuous period (T6) of 30 minutes is conducted, by way ofone example. In the other configuration conditions shown in FIG. 7, thecondition of the temperature of the furnace may be same as thetemperature condition shown in FIG. 5, but in the second meltingprocess, the evacuation of the space A is not conducted. As describedabove, in the case of the configuration condition example shown in FIG.7, the evacuation is not conducted in the second melting process,however, since the evacuating process conducted at the room temperature,the space A in the reduced-pressure state has the pressure lower thanthe outside pressure. Hence, the external force is applied so as todecrease the distance between the pair of glass panels 2 and 3. As aresult, like the configuration conditions shown in FIG. 5, in the secondmelting process, the frit seal 4 is sufficiently melted and thus theglass panels 2 and 3 are hermetically bonded firmly, and the slit 5 a ofthe partition 5 is closed, and consequently the space A is divided intothe outlet region B and the reduced-pressure region C.

Note that, when the melting process and the evacuating process under theother configuration conditions shown in FIG. 7 are conducted, the tip ofthe evacuation pipe 8 is subjected to the tip-off. Hence, even after theend of the second melting process, the outlet region B and thereduced-pressure region C each are kept in the reduced-pressure state.Thereafter, when the evacuation pipe 8 is removed, the outlet region Bhas the same pressure as the atmospheric pressure, while thereduced-pressure region C is kept in the reduced-pressure state.Consequently, the finished product of the multiple pane 1 shown in FIG.1 and FIG. 2 can be obtained.

As described above, according to the production method using the otherconfiguration conditions shown in FIG. 7, between the first meltingprocess and the second melting process, the evacuating process isconducted under a condition where the temperature of the multiple paneis set to the room temperature. Hence, the melting process and theevacuating process can be conducted independently, and thus the furnaceused in the melting process can be separate from the vacuum pump used inthe evacuating process. As a result, the furnace can be simplified anddownsized, and therefore the degree of sealing of the furnace can beimproved, it is possible to reduce the necessary power consumption andshorten time necessary for increasing the temperature. Further, thevacuum pump can be disposed at a position far from the furnace having ahigh temperature, and hence there is no need to take action to preventequipment for chucking a vacuum valve of the vacuum pump and/or theevacuation pipe from having high temperature, and therefore theproduction equipment can be simplified.

In contrast, in the second melting process, the space A is not beingevacuated, and thus the external force causing a decrease in thedistance between the pair of glass panels is weaker than that in thecase of the configuration conditions shown in FIG. 5. Therefore, it isnecessary to carefully control application status and viscosity of theglass frit for the frit seal 4 and the partition 5 so that after thesecond melting process the distance between the pair of glass panels 2and 3 becomes the predetermined distance and the slit 5 a of thepartition 5 is closed to successfully divide the space A into the outletregion B and the reduced-pressure region C. Further, it is consideredthat mechanical pressing force may be applied to at least one of theglass panels to keep the distance between the glass panels to thepredetermined distance, if necessary. Additionally, when the multiplepane is produced under the configuration conditions shown in FIG. 7, inthe step of removing the evacuation pipe 8, the outlet region Bspatially connected to the evacuation pipe 8 is kept in thereduced-pressure state. Therefore, it is necessary to pay attention toaccurate and safe removal of the evacuation pipe 8.

As described above, according to the production method of multiple panesof the present embodiment, the slit 5 a is provided to the partition 5as the air passage, and the slit 5 a is closed in the second meltingprocess, and thereby the space A formed between the pair of glass panelscan be divided into the outlet region B and the reduced-pressure regionC. In the present embodiment, an example in which one slit 5 a is formedin the almost central part of the partition 5 is shown, however, whenthe slit 5 a serving as the air passage is formed in the partition 5,the position of the slit, the number of slits and the like may beappropriately selected.

Further, the air passage formed in the partition 5 is not limited to theslit.

FIG. 8 is an enlarged plan illustrating a primary part including thepartition of the first modification exemplifying a configuration of thepartition provided with an air passage different from the slit.

The partition 5 of the first modification shown in FIG. 8 includes twoparts 5 b and 5 c. The parts 5 b and 5 c are connected to the frit seal4 at their one ends, and include curved parts in different directions atthe other ends opposite from the one ends connected to the frit seal 4.According to this structure, a gap 5 d between the curved parts servesas an air passage interconnecting the outlet region on the outlet sideand the reduced-pressure region in the space A.

The partition 5 is made of seal such as low-melting glass frit. The sealcan be applied to the predetermined position in the surface 2 a of theglass panel 2 facing the inside by controlling a position of anapplication nozzle which to discharge a paste of the seal from its tip.Hence, to form the slit 5 a with the predetermined width which is aninterval in the partition 5 formed continuously as shown in the planarconfiguration of FIG. 3, the nozzle is moved the predetermined distancewhile the discharge of the seal from the nozzle is tentatively stopped,and thereafter the discharge of the seal from the nozzle is startedagain. However, in some cases, it is difficult to accurately form thediscontinuous partition including the slit with the predetermined widthdue to some limitations such as the viscosity of the paste and theapplication width of the partition. In contrast, according to thepartition 5 of the modification shown in FIG. 8, opposite ends from theends connected to the frit seal 4 are curved in different directions soas to form the gap between the opposite ends, and the gap 5 d is used asthe air passage. Therefore, the control of the application position ofthe partition 5 by the nozzle can be facilitated, and hence, there is anadvantage that the partition 5 with the desired shape can be formedaccurately.

Note that, the width of the gap 5 d between the curved parts of theapplied glass frit, the length of the overlap of applied regions indifferent two directions, and the formation widths of the partitions 5 band 5 c with regard to the overlap can be appropriately selected inconsideration of the viscosity and the application height of the glassfrit, the width of the partition 5 fattened by pressing in the secondmelting process of melting the air passage by melting the partition, andthe like. Further, with regard to the shape of the opposite ends of theparts of the partition 5 from the ends connected to the frit seal 4, forexample, the opposite ends of the parts of the partition 5 may be formedas straight portions extending in different directions, and at leastparts of the straight portions are arranged in substantially parallel ata predetermined distance. In summary, it is possible to use variousconfigurations in which the partition formed continuously includes partsarranged at the predetermined distance, and the interval between theparts serves as the air passage to be closed when the partition isflattened by pressing in the second melting process.

FIG. 9 is an enlarged plan illustrating a primary part of the multiplepane including the partition of the second modification whichexemplifies another configuration of the partition provided with the airpassage.

The partition 5 of the second modification shown in FIG. 9 includes: twopartial partitions 5 e with one ends connected to the frit seal 4; aninterval 5 f defined by a gap between other ends of the two partialpartitions 5 e which are opposite from the one ends connected to thefrit seal 4; and a sealing part 5 g longer than the interval 5 f formedon at least one of both sides of the interval 5 f.

The partition 5 of the second modification shown in FIG. 9 includes atits central part the interval 5 f with a predetermined length greaterthan the width of the slit 5 a of the partition 5 shown in FIG. 3. Byway of one example, the predetermined length is greater than theapplication width of the partial partition 5 e.

In the partition 5 shown in FIG. 9, the interval 5 f formed in thecentral part is formed to have a length greater than the width of theslit 5 a shown in FIG. 3, and the sealing part 5 g for closing theinterval 5 f is disposed in a vicinity of the interval 5 f. The accuracynecessary for the length of the interval 5 f is not so high. Hence, evenwhen the application formation process of the partition 5 is simplifiedmore than a process of forming the slit 5 a shown in FIG. 3, it ispossible to form the partition 5 including the air passage allowingsuccessful division of the space A into the outlet region B and thereduced-pressure region C.

Note that, in the partition 5 of the second modification shown in FIG.9, the length of the interval 5 f, the length of the sealing part 5 g,and the distance between the partial partition 5 e between the sealingpart 5 g are appropriately selected in consideration of the material ofthe seal for the partition 5, the application formation method, theapplication height, the temperature conditions in the second meltingprocess, the width of the partial partition 5 e, and the like.

In the case of using the partition of the first modification shown inFIG. 8 or the partition of the second modification shown in FIG. 9, whenthe air passage formed in the partition is closed to divide the space Ainto the outlet region B and the reduced-pressure region C, thepartition 5 is wider at its part 5 h resulting from the closure of theair passage, as shown in FIG. 10. When the width of the partition 5 isincreased more than necessary, the partition 5 can be easily perceivedwhen the finished product of the multiple pane 1 is viewed. Further,there may be a problem that when melted the partition 5 may spread andleak out through the outlet 7. For this reason, it is preferable thatthe width of the part 5 h of the partition 5 in which the air passage isclosed is sufficiently controlled by adjusting the condition forapplication and formation of the partition 5.

As described above, the production method of multiple panes according tothe first embodiment of the present disclosure is described withreference to the instance where the frit seal serving as thehermetically-bonding member and the partition serving as the regionforming member are made by use of the same low-melting glass frit.

However, in the production method of multiple panes of the presentembodiment, the frit seal and the partition are not limited to beingmade of the same glass frit. For example, the partition serving as theregion forming member may be made by using glass frit with a meltingtemperature higher than a melting temperature of the frit seal servingas the hermetically-bonding member, for example. In more detail, theglass frit used for the frit seal and the glass frit used for thepartition have different melting temperatures, and further the heatingtemperature in the first melting process of melting the frit seal tohermetically bond the pair of glass panel is set to a temperature whichis equal to or more than the melting temperature of the frit seal and isequal to or less than the melting temperature of the partition, and theheating temperature in the second melting process of melting thepartition to divide the space A into the outlet region and thereduced-pressure region is set to a temperature which is more than themelting temperature of the partition. By doing so, it is possible toclearly distinguish by the temperature conditions the first meltingprocess of melting the frit seal to form the predetermined space betweenthe pair of glass panels from the second melting process of melting thepartition to close the air passage to divide the space between the pairof glass panels into the outlet region and the reduced-pressure region.

Alternatively, the hermetically-bonding member and the region formingmember may be made of seals which are other than glass frit and havedifferent melting conditions. As with this case, thehermetically-bonding member and the region forming member are made ofseals to be melted under different conditions, and only thehermetically-bonding member is melted in the first melting process andonly the region forming member is melted in the second melting process.Therefore, it is possible to avoid unexpected situations where theregion forming member is unfortunately melted in the first meltingprocess, and the air passage is narrowed and thus the evacuationefficiency for the space is likely to decrease, and in the worst casethe air passage is closed in the first melting process and thus thereduced-pressure region cannot have a sufficiently reduced pressure.

Note that, when each of the frit seal serving as thehermetically-bonding member and the partition serving as the regionforming member is made of low-melting glass frit, the meltingtemperature of the glass frit can be adjusted by components, sizes, andcontents of glass powder used for the glass frit and metal powercontained in the glass frit, and/or adjusting concentration and contentof a resin component used as a solvent.

Second Embodiment

The method of producing multiple panes of the second embodiment of thepresent disclosure is described with reference to the drawings.

The production method of multiple panes according to the secondembodiment is different from the production method of multiple panes ofthe aforementioned first embodiment in that a formation height of a fritseal 4 serving as a hermetically-bonding member formed on a surface 2 aof a rear glass panel 2 facing an inside is lower than a formationheight of a partition 5 serving as a region forming member. Note that,in the following text relating to the present embodiment, componentscommon to the present embodiment and the first embodiment are designatedby the same reference signs, and detailed explanations thereof may beomitted.

FIG. 11 and FIG. 12 are diagrams for describing the production methodfor the multiple pane of the second embodiment. FIG. 11 is a planillustrating a state in which the rear glass panel 2 and the front glasspanel 3 have not been hermetically bonded with the frit seal 4 yet. FIG.12 is a section illustrating a state in which the rear glass panel 2 andthe front glass panel 3 have not been hermetically bonded with the fritseal 4 yet. FIG. 12 is a view illustrating a sectional structure takenalong line Z-Z′ in FIG. 11. FIG. 11 is similar to FIG. 3 relating to thefirst embodiment. FIG. 12 is similar to FIG. 4 relating to the firstembodiment.

As shown in FIG. 11 and FIG. 12, in the production method of multiplepanes 1 of the present embodiment, the frit seal 4 in a frame shapeserving as the hermetically-bonding member is applied on a peripheralportion of a front surface 2 a of the rear glass panel 2, which is asurface facing the front glass panel 3. Further, the outlet 7penetrating through the glass panel 2 is formed in a corner of the rearglass panel 2. Additionally, an evacuation pipe 8 is provided to a rearsurface 2 b of the glass panel 2 to be connected to the outlet 7.

The partition 5 serving as the region forming member is formed on thefront surface 2 a of the glass panel 2 so as to surround the outlet 7together with the frit seal 4. In the present embodiment, the samelow-melting frit glass is used for the frit seal 4 hermetically bondingthe pair of glass panels 2 and 3 and the partition 5. However, anapplication height of the frit seal 4 is 1 mm by way of one example, andan application height of the partition 5 is 0.5 mm by way of oneexample, and in short, the application height of the partition 5 issmaller than the application height of the frit seal 4.

Note that, in the process of dividing the space between the glass panels2 and 3 by the partition 5 described later, the application height ofthe frit seal 4 and the application height of the partition 5 can beappropriately selected to an extent that melting of the frit seal 4 andthe partition 5 can be controlled. However, it is necessary that theapplication height of the partition 5 is greater than the height (e.g.,100 μm=0.1 mm) of the spacer 6 arranged at predetermined intervals onthe surface 2 a of the glass panel 2 facing the inside. For example, ina case where the frit seal 4 and the partition 5 are made of materialwhich has relatively high fluidity when melted, the application heightand width of the frit seal 4 are 0.5 mm and 5 mm, respectively and theapplication height and width of the partition 5 are 0.2 mm, and 3 mm,respectively, while the height of the spacer 6 is 0.1 mm. The paste usedfor forming the frit seal 4 and the partition 5 may be made of abismuth-based seal frit paste, which is described in the text relatingto the first embodiment, including: 60 to 75% of a glass component whichis composed mostly of bismuth oxide and includes 70% or more of Bi₂O₃, 5to 15% of each of B₂O₃ and ZnO, and 10% or less of other components; 20to 30% of zinc-silica oxide; and 5 to 15% of a mixture of organicsubstances such as ethylcellulose, terpineol, and polyisoutylmethacrylate. This frit glass has a softening point of 434° C.

FIG. 12 shows an assembly where the frit seal 4 and the partition 5 havenot been melted yet, and thus the front glass panel 3 is disposed on thefrit seal 4 having the largest application height.

This assembly is subjected to the first melting process in the furnaceunder the configuration conditions shown in FIG. 5 described in the textrelating to the first embodiment, for example. Through the first meltingprocess, the frit seal 4 is melted and thus the glass panel 2 and theglass panel 3 are hermetically bonded. Further, through the firstmelting process, the frit seal 4 is melted, and thus the height of thefrit seal 4 is decreased and the width of the frit seal 4 is increased.Hence, the distance between the front glass panel 3 and the rear glasspanel 2 is slightly decreased. However, as described in the textrelating to the first embodiment, the maximum achieving temperature inthe first melting process is 450° C. which is slightly higher than themelting temperature of 434° C. of the low-melting glass frit for formingthe frit seal 4 and the partition 5, and therefore changes in shape ofthe frit seal 4 and the partition 5 caused by melting are relativelysmall. Therefore, after the first melting process, a gap between the topof the partition 5 and the glass panel 3 caused by a difference inthickness between the frit seal 4 and the partition 5 has still existed,and thus the space formed between the pair of glass panels has beenstill one continuous space.

Next, the evacuation process shown in FIG. 5 is conducted, and thereforethe space is in a reduced-pressure state in which the degree of vacuumis 0.1 Pa or less. As described above, the gap remains between the glasspanel 3 and the top of the partition 5, and therefore the whole of theinside space A has the predetermined degree of vacuum.

Thereafter, as shown in FIG. 5, the second melting process having theachieving temperature of 465° C. which is higher than the achievingtemperature of the first melting process is conducted. According to thissecond melting process, the frit seal 4 is further melted. Theevacuation of the inside space A continues, and therefore intenseexternal force causing a decrease in the distance between the glasspanel 3 and the glass panel 2 acts, and consequently, the distancebetween the glass panels 2 and 3 is decreased until it is equal to theheight of the spacer 6. As a result of this second melting process, thepartition 5 is in contact with both the glass panel 2 and the glasspanel 3, and therefore the space A is divided by the partition 5 intothe outlet region B on the outlet side and the reduced-pressure region Cother than the outlet region. Note that, also in the present embodiment,in the second melting process, mechanical pressing force may be appliedto at least one of the glass panels to decrease the distance between theglass panels, if necessary.

The subsequent processes are same as those of the first embodiment. Inother words, after the vacuum pump is detached and the pressure of theoutlet region B becomes the atmospheric pressure like outside air, anevacuation pipe 8 is removed. In this regard, the reduced-pressureregion C is kept in the reduced-pressure state, and thus it is possibleto obtain the finished product of the multiple pane 1 shown in FIG. 1and FIG. 2 like the production method of the first embodiment.

As described above, in the production method of multiple panes of thesecond embodiment, the application height of the partition 5 serving theregion forming member is smaller than the application height of the fritseal 4 serving as the hermetically-bonding member. Therefore, the entireinside space formed between the pair of glass panels 2 and 3hermetically bonded can be made be in the predetermined reduced-pressurestate, and then divided into the outlet region and the reduced-pressureregion.

Note that, in the description relating to the above present embodiment,the frit seal 4 and the partition 5 are made of the same low-meltingglass frit, for example. However, also in the present embodiment, thefrit seal 4 may be made of material having its melting temperature lowerthan the melting temperature of the low-melting glass frit for formingthe partition 5.

Further, in the production method described in the text relating to thepresent embodiment, to successfully ensure the desired gap between theglass panel 3 and the top of the partition 5, the following method canbe used. In this method, at least one stopper for keeping the distancebetween the glass panel 3 and the glass panel 2 not less than apredetermined value may be disposed outside a region on which the fritseal 4 is applied. The stopper is used in the first melting process tokeep the predetermined distance, and thereafter in the second meltingprocess the stopper is removed. Thereby, the distance between the glasspanel 3 and the glass panel 2 becomes the predetermined distancedetermined by the spacer 6.

Further, like the first embodiment, the configuration conditions of themelting process and the evacuating process in the present embodiment maybe the other configuration conditions, shown in FIG. 7 with regard tothe first embodiment, where the temperature of the hermetically bondingglass is decreased down to the room temperature after the first meltingprocess and then the second melting process is conducted after theevacuating process is conducted outside the furnace.

As described above, according to the production method of multiple panesof the present disclosure, the space formed between the pair of glasspanels can be made be in the reduced-pressure state, and thereafterdivided by the region forming member into the outlet region includingthe outlet and the reduced-pressure region other than the outlet region.Hence, it is possible to produce by a simplified process, a multiplepane which includes the reduced-pressure region and therefore can havethe same properties as a multiple pane having the inside space with thereduced pressure, and nevertheless does not include the evacuation pipewhich is a protrusion protruded from a glass panel. Particularly, it isobvious that by making the outlet region smaller as possible and thereduced-pressure region larger as possible the multiple pane withsuperior advantageous effects given by the production method accordingto the above present disclosure can be obtained.

Note that, in the above description, the hermetically-bonding member andthe region forming member are made of material which melts and changesits shape when heated, such as glass frit. However, thehermetically-bonding member and the region forming member may be made ofvarious types of materials which solidify into a predetermined shape inresponse to stimuli such as rays of light such as ultraviolet rays. Inthis case, a high temperature process including the first meltingprocess and the second melting process as described in the text relatingto the above present embodiment is unnecessary, and production equipmentfor multiple pane can be greatly simplified.

Further, in the text relating to the aforementioned first embodiment,the air passage formed in the region forming member is exemplified by anair passage making planar separation such as a slit and an intervalbetween parts of the region forming member. However, depending onmaterial of the region forming member and methods of changing in shapeand solidifying the material, the air passage may be constituted by athrough hole penetrating through the region forming member.

Further, with regard to the production methods of multiple panes of thefirst embodiment and the second embodiment, in the examples describedwith referring to with reference to FIG. 5 and FIG. 7 for theconfiguration conditions of the melting process and the evacuatingprocess, the temperature of the hermetically bonded glass panels isdecreased temporally after the first melting process and then theevacuating process is conducted. However, in the production method ofmultiple panes of the present disclosure, it is possible to useconfiguration conditions where after the first melting process, thetemperature of the pair of glass panels hermetically bonded is notlowered but is kept or is increased and then the evacuating process isconducted and thereafter the second melting process using highertemperature than the first melting process is conducted. By doing so, itis possible to shorten lead time for the melting process and theevacuating process. Note that, to perform the evacuating process withoutdecreasing the temperature of the hermetically bonded glass panels, itis very important that the reduced-pressure region formed by dividingthe space between the pair of glass panels is made be in a sufficientlyreduced pressure state by accurately controlling the timing of closingthe air passage formed in the region forming member.

Further, in the production method of multiple panes of the firstembodiment and the second embodiment, with regard to a case where thepartition serving as the region forming member is made of material witha different melting point from material of the hermetically-bondingmember or has a different application height from the frit seal, anexample in which part is constituted by the region forming member in thesame state except the hermetically-bonding member disposed at theperipheries of the pair of glass panels is described. However, in theproduction method of multiple panes of the present disclosure, in orderto maintain the inside space A as one continuous space after completionof the first melting process, the region forming member may be made sothat one part of the region forming member is made of material with adifferent melting point from material of the hermetically-bonding memberand the air passage is formed in this part and another part of theregion forming member is made of the same material as thehermetically-bonding member. Further, in a similar manner, the regionforming member may have one part with a smaller application height thanthe hermetically-bonding member and another part with the sameapplication height as the hermetically-bonding member. Further, thematerial and the application height of the region forming member may bedifferent from those of the hermetically-bonding member.

FIG. 13 is a diagram illustrating the state of the region forming memberof the finished product of the multiple pane produced by the productionmethod according to the present disclosure.

FIG. 13 shows a photograph of a sample low-melting glass frit parts 21arranged with a slit 22 with a predetermined length in-between aremelted in the melting process and thereby slit is closed by melted part23. In more detail, the low-melting glass frit parts are made of thepaste described in the texts relating to the first and secondembodiments, the application width is 5 mm, the slit width is 2 mm, andthe application height is 0.5 mm. The sample was prepared by subjectedto the melting process at 465° C. for 30 minutes in a furnace. Notethat, the glass panels are two soda-lime glass panels with a thicknessof 3 mm. In the melting process, external force causing a decrease in adistance between the pair of glass panels was not applied. Further, inthe sample shown in FIG. 13, to facilitate taking photographs, the glassfrit parts 21 with the slit 22 in-between were formed at peripheralregions of the glass panels.

As shown in FIG. 13, after melting of glass frit, the part 21 which ispreliminarily formed by application has a relatively light color, andthe part 23 which is melted and is solidified has a relatively darkcolor, and thus it is possible to distinguish the part 21 from the part23. As a result of check by the present inventors with microscopes, itis acknowledged that the part of low-melting glass preliminarily appliedshows a pattern of fine particles whereas the part low-melting glasswhich was melted and flowed once shows a pattern of fine lines. It isconsidered that these patterns are formed by glass fine particles andpores contained in the low-melting glass frit paste. Further, it isconsidered that a difference between these patterns depends on amountsof movement from the original application position. It is consideredthat such a difference in surface states causes a difference in colorwhich can be observed with naked eyes.

As apparent from the above, with regard to the low-melting glass frit,the part which was preliminarily applied and the part which was oncemelted and liquefied and again was solidified are in different surfacestates. Even in the finished product of the multiple pane, thedifference between the surface states appears as a difference in colorby irradiation with particularly intense light. Further, in a case wherethe parts of low-melting glass frit have different application heights,such a difference between the parts may appear as a difference in thesection of the finished product, and especially appear as a differencein a width of the section or the degree of spread of a portion incontact with the glass panel. As understood from the above, the multiplepane produced by the production method of multiple panes of the presentdisclosure can be identified from multiple panes produced by othermethods, based on whether the multiple pane includes the outlet regionwith the external pressure and the reduced-pressure region kept in thereduced-pressure state, and observation of the state of the regionforming member between the two regions.

Further, a method of melting the hermetically-bonding member and theregion forming member may include laser sealing of fusing particularparts of the hermetically-bonding member and the region forming memberby heating with laser, in addition to a method of placing the whole ofglass panels inside the furnace as described in the texts relating tothe embodiments, for example. According to a method of fusing particularparts of the hermetically-bonding member and the region forming memberby applying predetermined heat from outside by laser sealing or othermethod, it is easy to selectively melt the hermetically-bonding memberand the region forming member at predetermined regions. Hence, it can beexpected that melting control in the production process where only thehermetically-bonding member is melted in advance and then the regionforming member is melted is successfully conducted. Further, in a casewhere the hermetically-bonding member is melted and bonded in thefurnace and thereafter the inside space is evacuated and then the regionforming member is melted by laser sealing so as to divide the insidespace into the outlet region and the reduced-pressure region, it ispossible to produce multiple pane at a lowered cost and with asimplified device.

Further, in the texts relating to the above embodiments, a method ofdisposing the spacers on the region surrounded by thehermetically-bonding member to keep the gap between the pair of glasspanels is described. Alternatively, height keeping member correspondingto the spacer may be disposed at a region where the hermetically-bondingmember is formed.

FIG. 14 relates to a case where glass beads serving as the heightkeeping member with the same height as the spacer are disposed at aregion where the frit seal serving as the hermetically-bonding member isformed, and shows a cross section illustrating a state in which theregion forming member is melted and the inside space is divided. LikeFIG. 6 used for explanation of the first embodiment, FIG. 14 shows themultiple pane in which the frit seal and the partition is meltedperfectly once.

As shown in FIG. 14, with regard to the region where the frit seal 4 isformed, spherical glass beads 9 with a diameter equal to the height ofthe spacer 6 are disposed. In this case, it is possible to reduce adifference in the distance between the pair of glass panels 2 and 3between a part at which the spacers 6 are disposed and a peripheral partat which the glass frit 4 is formed. By doing so, it is possible tosuccessfully prevent a curve of the finished product of the pair ofglass panels 2 and 3, and thus residual stresses of the glass panels 2and 3 can be reduced and the strength of the multiple pane can beimproved. Further, it is possible to avoid a problem where the distancebetween the glass panels 2 and 3 becomes smaller than the predetermineddistance at the region at which the frit seal 4 is applied, and thus thefrit seal 4 is pressed and flattened and thereby widened, andconsequently the frit seal 4 can be easily perceived by a user, forexample.

Note that, as a method of disposing the height keeping member at theregion at which the hermetically-bonding member is formed, it ispossible to use a method of mixing the glass beads 9 in the paste forapplication of the frit seal 4, and disposing the glass beads 9 at thesame time of applying the frit seal 4. Further, the height keepingmembers may be disposed in advance at the region at which the frit seal4 is formed, by a dispersion method similar to the method of disposingthe spacers 6 or photolithography at the same time of disposing thespacers, and thereafter the frit seal 4 can be applied to cover theheight keeping member.

The height keeping member described in FIG. 14 is disposed at the regionat which the hermetically-bonding member is formed, and thus differentlyfrom the spacers, problem in which the height keeping member isperceived by a user and causes poor appearance of the multiple pane isless likely to occur. Hence, the height keeping member may becylindrical member with the relatively large area or continuous memberwith a predetermined length in a peripheral direction of the glass panellike the partition. With regard to a method of disposing and formingsuch a height keeping member with the large area in a plan view, theaforementioned photolithography is preferable. Further, depending on thesize of the multiple pane and the thickness of the glass panel, it ispossible to produce the multiple glass which includes the height keepingmember but does not include the spacers.

Further, in the texts relating to the above embodiments, an example inwhich one outlet formed at a vicinity of a corner of one glass panel isused as the outlet formed in the glass panel is described. However, thenumber of outlets is not limited to one. For example, in the case of themultiple pane with the large area, in view of evacuation efficiency, twoor more outlets may be formed. In this case, two or more region formingmembers are disposed to surround the respective outlets, and then theinside space is divided into two or more outlet regions and one reducedpressure region or in some cases two or more reduced pressure regions.In a case where two or more outlets are formed, at least one outlet maybe formed in each of glass panels.

Further, instead of forming the outlet in the glass panel, apredetermined gap is provided to the hermetically-bonding member formedbetween the peripheries of the glass panels, and air can be evacuatedfrom the inside space by using this gap as the outlet. Particularly, inthe production method of multiple panes of the present disclosure, thespace between the pair of glass panels is divided by the region formingmember, and thus there is no need to keep the outlet region in thereduced-pressure state with regard to the finished product. Therefore,for example, an interval similar to the interval described as the airpassage of the region forming member may be formed in thehermetically-bonding member. Alternatively or additionally, a hollowcylindrical member may be disposed in the hermetically-bonding memberinstead of the spherical glass bead as the height keeping member so asto penetrate the hermetically-bonding member, and the inside space ofthe hollow cylindrical member may be used as the outlet. Note that, twoor more outlets may be formed in the hermetically-bonding member, andalternatively, at least one outlet may be formed in each of the glasspanel and the hermetically-bonding member.

Further, in the texts relating to the above embodiments, the method ofconnecting the evacuation pipe to the outlet and reduce the pressure ofthe inside space with the evacuation pipe is described. Use of theevacuation pipe facilitates connection with the vacuum pump, and thusthe pressure of the space between the pair of glass panels can bereduced by a conventional evacuation method. However, the evacuationpipe is dispensable for evacuating the space between the pair of glasspanels. For example, by hermetically connecting the vacuum pump to thehermetically bonded glass panels with a ring member with predeterminedflexibility allowing the ring member to be in close contact with asurface of the glass panel at a vicinity of a part in which the outletis formed, the inside space can be made be in the reduced-pressure statewithout using the evacuation pipe.

Further, in the multiple pane produced by the production method ofmultiple panes of the present disclosure, already established techniquesof multiple panes such as forming functional films made of organic orinorganic material in order to give various types of optical functionssuch as reflection prevention and absorption of ultraviolet or thermallyinsulating properties to the glass panels can be added or applied. Forexample, by coating a front surface or a rear surface of at least one ofthe glass panels constituting the multiple pane with a thin film made ofoxide such as tin oxide (SnO₂), indium tin oxide (ITO), and zinc oxideby a conventional method such as CVD (chemical vapor deposition) or afilm of silver and oxide layers stacked alternately by a sputteringdevice, an infrared reflection film reflecting a large amount of lightin an infrared region can be provided, and thus the thermally insulatingproperties of the multiple pane can be improved. Further, in this case,when the space has a hollow structure, or is of low thermal conductivematerial, it is possible to obtain the multiple pane with higherthermally insulating properties.

Further, it is possible that a getter member for improving a degree ofvacuum is disposed in an inside space A of a multiple pane. Further, amultiple pane with a curved shape as a whole can be realized by use ofcurved glass panels curved in one direction or two or more directions asglass panels constituting a multiple pane.

Furthermore, it is possible to form a multiple pane in which three ormore glass panels are stacked at predetermined intervals as a whole byreplacing at least one of the pair of glass panels by another multiplepane. In this case, it is sufficient that at least one part of a stackedmultiple pane in the thickness direction may be a multiple pane producedby the production method of the present disclosure. Therefore, amultiple pane produced by the production method of the presentdisclosure may be used in various ways, and for example, a multiple panewhere a space between glass panels is filled with inert gas, a multiplepane produced by the production method of the present disclosure oranother method, or a multiple pane in which glass panels are stacked atpredetermined intervals but spaces therebetween have atmosphericpressure may be stacked on a multiple pane produced by the productionmethod of the present disclosure.

The multiple panes produced by the production method of multiple panesof the present disclosure as described above have high thermallyinsulating effects, and can be preferably applied to window panes aseco-glass easy in handling. Further, for example, when multiple panesproduced by the production method of multiple panes of the presentdisclosure are disposed in doors of refrigerators and freezers, themultiple panes have high thermally insulating effects, and thus allowcheck of insides of refrigerators and freezers without interferingfunctions of refrigerators and freezers. Hence, it is expected that themultiple panes are used in household and business.

Note that, techniques of dividing the glass panel while keeping theevacuated space in the reduced-pressure state in accordance with thepresent disclosure can be applied to, in addition to multiple panes,display devices prepared by evacuating predetermined spaces, such asplasma display panels and fluorescent indication devices, and it ispossible to produce finished products of display devices devoid ofprotrusions such as evacuation pipes like products of the presentdisclosure.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent teachings.

As described above, it is possible to produce multiple panes easy inhandling in a simplified manner, and therefore the production method ofmultiple panes of the present disclosure is useful.

1. A production method of multiple panes comprising: hermeticallybonding, with a hermetically-bonding member, peripheries of paired glasspanels disposed facing each other at a predetermined distance to form aspace to be hermetically enclosed between the glass panels; evacuatingair from the space through an outlet to make the space be in areduced-pressure state; and dividing, after the space is made be in thereduced-pressure state, the space by a region forming member into anoutlet region including the outlet and a reduced-pressure region otherthan the outlet region.
 2. The production method of multiple panes ofclaim 1, wherein: the region forming member includes an air passageinterconnecting the outlet region and the reduced-pressure region undera condition where the space is formed; and after the space is made be inthe reduced-pressure state, the space is divided into the outlet regionand the reduced-pressure region by closing the air passage.
 3. Theproduction method of multiple panes of claim 2, wherein: the air passageis an interval of the region forming member formed in a discontinuousshape; and after the space is made be in the reduced-pressure state, theinterval is closed by melting the region forming member.
 4. Theproduction method of multiple panes of claim 1, wherein: a formationheight of the region forming member before being melted is less than aformation height of the hermetically-bonding member before being melted;and after the space is made be in the reduced-pressure state under acondition where the pair of glass panels are hermetically bonded bymelting the hermetically-bonding member, the space is divided into theoutlet region and the reduced-pressure region by the region formingmember by decreasing the distance between the pair of glass panels. 5.The production method of multiple panes of claim 1, wherein: a meltingtemperature of the region forming member is higher than a meltingtemperature of the hermetically-bonding member; the space is formed byhermetically bonding the pair of glass panels at a temperature causingmelting of the hermetically-bonding member to form the space; and afterthe space is made be in the reduced-pressure state, the space is dividedinto the outlet region and the reduced-pressure region by melting theregion forming member at a temperature causing melting of the regionforming member.
 6. The production method of multiple panes of claim 1,wherein: after the space is formed by conducting melting inside afurnace to melt the hermetically-bonding member, and subsequently thespace is made be in the reduced-pressure state outside the furnace, thespace is divided into the outlet region and the reduced-pressure regionby conducting again melting inside the furnace to melt the regionforming member.
 7. The production method of multiple panes of claim 1,wherein the outlet is formed in at least one of the pair of glasspanels.
 8. The production method of multiple panes of claim 1, wherein:the space is made be in the reduced-pressure state by use of anevacuation pipe connected to the outlet; and the evacuation pipe isremoved after the space is divided into the outlet region and thereduced-pressure region.
 9. The production method of multiple panes ofclaim 1, wherein the hermetically-bonding member and the region formingmember are made from glass frit.
 10. The production method of multiplepanes of claim 1, wherein a spacer for keeping a gap between the pair ofglass panels is disposed on a surface of at least one of the pair ofglass panels.
 11. The production method of multiple panes of claim 1,wherein a height keeping member for keeping a gap between the pair ofglass panels is disposed at a portion on which the hermetically-bondingmember is to be formed.
 12. The production method of multiple panes ofclaim 10, wherein the spacer is formed by photolithography.
 13. Theproduction method of multiple panes of claim 11, wherein the heightkeeping member is formed by photolithography.